Conclusions
We've now had a look at AMD's first response to Nehalem, and well, it's not bad. The six-core Opteron 2345 can't quite match the Xeon X5550 in overall performanceand although these products are nearly the same price, the Xeon X5550 isn't the highest Nehalem speed grade. That honor would fall to the Xeon W5580 processor that appeared in some of our benchmark results. In terms of raw performance in a 2P system, Nehalem still reigns supreme.

Yet Istanbul should be a clear improvement over Shanghai for many workstation-class workloads and most server-class workloadsi.e., those that are essentially parallel and widely multithreaded. The Opteron 2435 manages to deliver this higher performance not just within the same power envelopes, but quite empirically with almost the exact same measured power consumption as the Opteron 2389.

This combination yields a nice increase in power efficiency, which was enough to put our Istanbul-based test system in the same territory as our Xeon X5550 system. The competition between the two was remarkably close in SPECpower_ssj, and the Istanbul system required notably less energy to render the Cinema 4D sample scene in Cinebench. So despite that fact that Intel leads in outright performance, the Opteron 2435 is entirely competitive on the power-efficiency front, with lower peak power draw, to boot. Those who evaluate systems strictly on this basis would do well to keep Opterons in the mix.

And if you have existing, compatible Socket F servers, the Istanbul Opterons should be an excellent drop-in upgrade. They're a no-brainer, really, when one considers energy costs and per-socket/per-server software licensing fees.

AMD has a tougher sell to make when it comes to brand-new systems. The Nehalem Xeons offer higher peak performance with a similar energy-efficiency proposition. Still, Istanbul at least keeps the Opteron in the conversation, which makes the outlook for AMD seem substantially less apocalyptic than it did several short months ago.